Book Title help when collecting part of a series.

[Dobby]

"Intergalactic Dating Agency" is on the cover of each of the books in the series. Since that hasn't been used as part of the titles prior to now, I'd entitle this edition Dragon Brides Vol. I: Crux / Ranger / Saber (Dragon Brides #1-3)

ETA: This is the way I've seen it done on other "multi-volume" collections. Most collections don't use a Volume notation, but I've run across some that do.